Self service checkout systems are widely used in retailing, and provide opportunities for significant labor savings by merchants. However, the use of such systems, unless properly managed, provides increased opportunities for theft by unscrupulous customers. In order to provide for efficient and profitable use and customer satisfaction, self service systems must be able to reduce opportunities for undetected theft while avoiding excessive referral of transactions to human operators. In addition, employee operated checkout systems may also provide opportunities for an unscrupulous customer to engage in theft by altering product identification or security features of products or their packaging without detection by an employee operating a checkout station.
One commonly used mechanism for preventing costly thefts is the use of security tags. Security tags are often used on high priced or easily concealed products, but may be used on any desired product. A tag is affixed to a product or its packaging in such a way that the tag is difficult to remove. The tag typically triggers an alarm when carried past a checkpoint unless it is first deactivated.
Security tags are typically deactivated by passing them through a magnetic field generated by a deactivation device. The magnetic field through which the tags pass may extend some distance, such as several inches, from the deactivation device. One way for a thief to steal a high priced product is by concealing the product within a larger, typically lower cost, product. For example, a thief might conceal a personal audio player inside a substantially larger product, such as a storage container. Self checkout systems typically include weight matching features in order to detect attempts at theft. Such weight matching allows for deviations, within some tolerance, between a weight reading and an expected weight. If a smaller product is concealed within a substantially larger product, in this case, the personal audio player within the storage container, the deviation in weight reading caused by the presence of the smaller product may not be detected by a weight matching feature. If the checkout station includes a deactivation device that is always operating or that operates whenever a product is entered into a transaction, the thief may purchase the suitcase and deactivate a tag affixed to the personal audio player concealed within the suitcase. The thief would be able to deactivate the tag without detection and without entering the personal audio player into the transaction.
Another strategy used by thieves is to falsify a bar code attached to a product presented for purchase. Such falsification may be accomplished by creating a false bar code, or by taking a bar code from another product. The falsified bar code typically identifies a product having a similar weight to, but a lower price than, the product to which the bar code is fraudulently attached. Such a scheme allows a customer to fraudulently avoid paying the correct price for the product.